Suspect short in water heater


  #1  
Old 12-06-03, 12:06 PM
Cracker Box
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Suspect short in water heater

I attempted to contact you about a week ago but I have not
received any reply so I am not sure if my attempt was successful.

My 60 gallon water heater is two years old. It has two 4500 watt
elements which is powered by 10/3 (w/ground) copper wire. It
frequently blows 30 amp fuses. I have inspected the wiring and
the connecting terminals and all appear to be okay. I have
tested both elements for continuity and they tested okay. I then
removed both elements for a visual inspection and I did not see
any obvious defects. However, I had a little difficulty removing the top element and once I got it out I found that it was bent
in an approx. 90 deg. L shape rather than the normal U bend.

After replacing the fuse it would operate for a few days and
other times only 3 or 4 hours.

In an effort to rule out the fuse box (I did have a defective fuse
box a few years ago at another location) I connected a 40 gallon
water heater containing two 3000 watt elements protected by
15 amp fuses and have not had a problem for 3 weeks now.

My question: Is it possible for one of the elements to short out
and still pass a continuity test?

I am mystified and would appreciate your advice. Thanks a heap.

Cracker Box
 
  #2  
Old 12-06-03, 01:40 PM
rob1kva
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Although a direct short will blow a fuse instantly, did you notice any burn marks on any of the connections or on the element with the bend? Do fuses blow on both legs of the circuit? If the H.W heater is only 2yrs. old it may still be under warranty & may have a factory defect.
 
  #3  
Old 12-08-03, 08:43 PM
Cracker Box
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Reply to Suspect short in water heater

Both legs have blown the 30 amp fuses but only one at a time.
Each time I would only replace one but it has occured on both
the red wire and the black wire.

I did not notice any burning at either element terminals but will
examine again.

Yes, the heater is still under warranty but if it is only a defective
element I would rather pay the nominal cost of purchasing a new
one than having to install another heater. Also, trying to get
satisfaction on warranties is not always a simple or swift matter.

From the little I know of electric water heaters the problem
could only be with the elements, the wiring or the thermostats.
What else is there?

Thanks for your help . . . Cracker
 
  #4  
Old 12-09-03, 12:15 PM
M
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Have you followed the cable back to the panel (as far as you can) to make sure it is in good shape?

Would be interested to know if the blown fuses are the result of a short circuit or an overload. Is it possible that your upper thermostat is faulty and is somehow putting power on both elements at the same time, thus creating an overload?

Did you pull the thermostats away from the tank and inspect the back sides? If there is a short circuit somewhere it could possibly be there.

Have you inspected the fuse holders and wiring terminals in the fuse box carefully and looked for hot spots? Can you move the wires in the fuse box to a different set of fuse holders (temporarily, for testing purposes) - maybe the dryer fuse hoders?

Did you check the connections in the junction box at the top of the heater?

Is there a disconnect or switch? Have you checked there?
 
 

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